Our sources tell us ... producers brought Browning in to test her for a full-time gig on the show ... and she brought Rice Jr. because she thought it would help her chances. But things took a turn for the worse when they began drinking -- with the ladies complaining to producers that Glen was getting aggressive and making the women uncomfortable.

We're told Tammy went to ask Glen to leave -- and as one source says, "He lost it." Our sources say Glen went to confront one of the housewives -- and Tammy tried to get in the way to stop him -- but he wouldn't stop and knocked her to the ground. Tammy smacked her head pretty hard and began to cry.

We're told the whole thing was captured on video ... in fact, footage of Tammy reeling in pain was used in the promo for the new season.

Tammy was eventually taken to the hospital for evaluation -- where doctors determined she was fine, no concussion. But later, Tammy and Glen returned to the home -- where the housewives made it clear Glen wasn't welcome. An argument ensued and cops were called to the scene.

Things eventually calmed down -- no one was arrested -- and Glen left without further incident. But our sources say Glen was told he was NOT welcome back and Tammy did not get a featured role on the show.